Current industry practice to remove cartons automatically from trays utilizes one of two types of designs. The first design involves stopping the tray, lifting the carton up on fingers and raking the carton off the fingers. This design requires the tray to come to a stop thereby limiting the potential throughput rate. In this design, a single tray removal device can have the ability to process multiple tray sizes but imposes certain limitations to the number of sizes of trays that can be processed by a single tray removal device. It also at times imposes additional limitations on the orientation of trays with regard to the side or dimension of the tray that first approaches the tray removal device.
A second design is characterized by previous attempts to utilize a continuous process involving a “scraping” type device to lift the carton up and onto a powered belt. This design requires a grid of raised platforms on the bottom of the tray. The platforms form an elevated surface upon which the carton can rest. The fingers of the scraping device reach between the platforms and under the elevated carton. As the tray moves on the powered belt, the back lip of the tray drives the carton up the inclined scraper surface formed by the assembly of fingers and onto a powered belt. This design requires significantly increased vertical height in the tray design, resulting in the tray itself occupying a significant amount of space in the storage facility. It also requires the use of relatively uniform size cartons to allow the back edge of the tray to drive the carton far enough up the inclined surface to engage the powered takeaway conveyor. This design also is limited in that each tray removal device can process only one size tray thus requiring multiple devices as a means to process multiple tray sizes.
The cartons handled by automated systems can vary in size, therefore it is a goal of carton removal systems to provide and use trays that are of a size that will contain the carton but are no larger than necessary to do so. To the degree that the tray is larger than the carton, some space in the storage facility may be wasted. In these applications a wide variety of carton sizes are used. In order to maximize the utilization of the storage volume, multiple tray sizes are required.